1. Field of the Invention
The present invention is directed to a burner configuration, and more particularly to a burner design adapted for use in rotary dryers, such as asphalt dryers, and in boilers and furnaces, which design enables the efficient burning of gaseous fuel or fuel oil.
2. Description of Related Art
Illustrative of the prior patents issued in the field of burners used, for example, in rotary dryers, furnaces, and boilers, are the following patents:
______________________________________ U.S. Pat. No. Inventor ______________________________________ 4,298,337 Butler et al. 4,341,512 Wojcieson et al. 4,431,403 Nowak et al. 4,443,182 Wojcieson et al. 4,559,009 Marino et al. 5,083,382 Brashaars 5,192,204 Musil 5,259,755 Irwin et al. 5,263,849 Irwin et al. 5,415,539 Musil ______________________________________
Companies such as Hauck Manufacturing Co. and Gencor are involved in the production and sale of burners used in rotary dryers, and companies that are presently selling burners for use in boilers and furnaces are Coen and Industrial Combustion/Webster.
Throughout the time period in which all of the above patents issued, and continuing through the present, the goals sought to be achieved in developing new burner designs are to provide a compact and efficient combustion burner, a burner having a large turn-down ratio, a burner that achieves greater flame stability, a burner that efficiently and readily burns both liquid and gaseous fuel, and a design that provides dependable operation and economical manufacture.
While several of the designs disclosed in the above patents have proven to be commercially viable, there is a continuing need for further improvements and enhancements in burner design in order to better achieve the desired goals.
It is therefore a principal object of the present invention to provide a burner design that achieves a high overall turn-down ratio when burning both liquid and gaseous fuel, by providing the burner with a unique nozzle design and improved air swirl adjustability.
It is an additional principal object of the present invention to provide a burner design that will burn both liquid and gaseous fuel through the same primary body, and which can be used to burn stoichiometrically or to burn with excess air or low air-fuel ratios.
It is a further important object of the present invention to provide a burner design that can be used under a wide variety of firing conditions, including being capable of firing liquid (such as oil) or gaseous fuel at lower horsepowers and using the same primary body for either fuel.
It is an additional important object of the present invention to provide a burner design in which the air capacity of the burner can be changed with minimal effort, thereby effectively providing a plurality of burner sizes for a single atomizing air body.
It is an additional important object of the present invention to provide a burner design in which the adjustment or trim of the flame oxygen content can be accomplished by direct movement of burner components, or by changing the available pressures to those components from an upstream valve.
It is yet an additional important object of the present invention to provide a burner design in which the primary firing body is designed to be capable of being stacked or clustered with additional identical primary bodies in constructing larger sized burners.